HR: 15:25h
AN: A42D-08 [PDF]
TI: Changes of Methane and Nitrous Oxide in the Atmosphere : new Constraints From Stable Isotope Analyses
in Polar Firn and ice.
AU: * bernard, s
EM: bernard@lgge.obs.ujf-grenoble.fr
AF: CNRS - Laboratoire de Glaciologie et Geophysique de l'Environnement, 54, rue Moliere - Domaine
Universitaire - BP96, Saint Martin d'Heres, 38402
France
AU: Kaiser, J
EM: kaiser@princeton.edu
AF: Princeton University - Department of Geosciences, Washington Road, Princeton, NJ 08544 United States
AU: R”ckmann, T
EM: T.Roeckmann@mpi-hd.mpg.de
AF: Max-Planck-Institut fr Kernphysik - Bereich Atmosph„renphysik, Saupfercheckweg 1, Heidelberg, 69117
Germany
AU: Chappellaz, J
EM: jerome@lgge.obs.ujf-grenoble.fr
AF: CNRS - Laboratoire de Glaciologie et Geophysique de l'Environnement, 54, rue Moliere - Domaine
Universitaire - BP96, Saint Martin d'Heres, 38402
France
AU: Barnola, J
EM: barnola@lgge.obs.ujf-grenoble.fr
AF: CNRS - Laboratoire de Glaciologie et Geophysique de l'Environnement, 54, rue Moliere - Domaine
Universitaire - BP96, Saint Martin d'Heres, 38402
France
AB:
Methane and nitrous oxide are two greenhouse gases playing a major role in atmospheric chemistry ; methane largely affects
the oxidative capacity of the atmosphere whereas nitrous oxide participates in many atmospheric chemical reactions involving
O$_{3}$ and NO$_{x}$ in the stratosphere. A sharp increase in the mixing ratios of both gases has been observed since the
beginning of the pre-industrial era, implying an increase of anthropogenic sources.
Although these gases are important in global climate changes, their budget remains poorly known. The evolution of their
isotopic composition in the atmosphere brings additional constraints as it represents the final signature of their budgets
and reflects changes in the relative contribution of sources and sinks.
We have measured preindustrial air from polar firn air and ice cores that will lead to the long term evolution of these
gases. A continuous flow technique is used at the Laboratory of Glaciology and Geophysics of Environment (LGGE) in Grenoble,
France to measure $\delta$$^{13}$CH$_{4}$, whereas a similar technique is used at the Max Planck Institute for Nuclear
Physics, in Heidelberg, Germany to measure $\delta$$^{15}$N$_{2}$O and $\delta$N$_{2}$$^{18}$O. Samples from both Antarctica
(Vostok, Dome C, Berkner Island) and Greenland (North GRIP) were used. We will present these results and their tentative
interpretation based on a diffusion model of gas isotopes in polar firn and on simple atmospheric box approaches.
UR: http://w3.agu.org
DE: 0322 Constituent sources and sinks
DE: 0325 Evolution of the atmosphere
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting